Looking at an enhanced picture of the blades, they show deep pitting, the lighter areas are not clean metal...perhaps a build up of chemical salts from soil. Looks as if these were 'dug up' ........probably months after they were deliberately buried
I am also assuming that 'pre-burial' the blades were chemically 'attacked' to jump start the aging process.
Who said 'gardening' was a waste of time.....I'm off to 'plant' a few swords...now, where's my spade
